The construction industry, as a major consumer of resources and energy, accounts for about 40% of global carbon emissions. The concept of a circular economy (CE) is one effective means to address this issue. The entire lifecycle of a building includes: material production, construction, operation, and demolition. The production of building materials emits the largest proportion of carbon dioxide, followed by the operational phase, while construction (including demolition) has the smallest proportion. However, it is crucial to note the waste phase after demolition, where building materials are typically disposed of through incineration or landfill, leading to significant carbon emissions and environmental degradation. Therefore, carbon emissions generated during both the production and waste phases of the construction industry cannot be overlooked. This article employs a combined approach of practice and research, using the Circular Pavilion as a case study. From the design stage, reducing resource usage and carbon emissions are considered crucial factors. Reversible design, modularity, and the use of recycled materials are employed to reduce the emissions of “embodied carbon” and enhance material reuse. To validate the effectiveness of recycled materials in reducing greenhouse gas (GHG) emissions, this study calculates the material usage and carbon emissions during the production, transportation, and waste phases of the Circular Pavilion, Concrete Pavilion, and Steel Pavilion. The Circular Pavilion accounts for 34% and 3.5% of the total carbon emissions of the Concrete Pavilion and Steel Pavilion, respectively. In conclusion, the practical implementation of reversible design and recycled materials based on the concept of a circular economy is key to transitioning the construction industry from environmentally harmful impacts to eco-friendly practices. This establishes an effective method for resource reuse and carbon dioxide reduction in the construction sector, allowing waste resources to re-enter production and manufacturing processes, thereby reducing natural extraction, waste disposal, and energy consumption. Future applications of this method in the construction field involve establishing multidimensional composite design models and conducting feasibility assessments with upstream and downstream supply chains to support the realization of circular cities.